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Alpha Lupi (α Lupi, α Lup) is the brightest star in the southern constellation of Lupus. According to the Bortle Dark-Sky Scale, its apparent visual magnitude of 2.3〔 makes it readily visible to the naked eye even from highly light-polluted locales. Based upon parallax measurements made during the Hipparcos mission,〔 the star is located at a distance of around from Earth.〔 Alpha Lupi is a giant star with a stellar classification of B1.5 III.〔 It has about ten times the mass of the Sun〔 but is radiating 25,000〔 times the Sun's luminosity. The outer atmosphere has an effective temperature of 21,820 K,〔 which gives it the blue-white glow of a B-type star. In 1956 it was identified as a Beta Cephei variable by Bernard Pagel and colleagues,〔 which means it undergoes periodic changes in luminosity because of pulsations in the atmosphere. The variability period is 0.29585 days,〔 or just over 7 hours, 6 minutes. The magnitude varies by about 0.05, or about 5% of the total luminosity. A small star situated near Alpha Lupi may just be an optical companion. This star is a proper motion member of the Upper-Centaurus Lupus sub-group in the Scorpius-Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.〔 This is a gravitationally unbound stellar association with an estimated age of 16–20 million years. The association is also the source of a bubble of hot gas that contains the Sun, known as the Local Bubble.〔 ==Etymology== In Chinese, Kekouan (), meaning ''Imperial Guards'', refers to an asterism consisting of α Lupi, γ Lupi, δ Lupi, κ Centauri, β Lupi, λ Lupi, ε Lupi, μ Lup, π Lupi, and ο Lupi .〔 ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.〕 Consequently, α Lupi itself is known as (, (英語:the Tenth Star of Imperial Guards).).〔 (香港太空館 - 研究資源 - 亮星中英對照表 ), Hong Kong Space Museum. Accessed on line November 23, 2010.]〕 R. H. Allen had opinion that this star was listed it in the Chinese asterism ''Yang Mun'' or ''Men''（南門), meaning "the South Gate", in his work ''Star-Names and their Meanings''. But in Chinese astronomy, 南門 is located in ''Horn'' mansion and consisted by α and ε Centauri. ''Yang Mun'' was translated in Pinyin as 陽門, meaning "the ''Yang'' Gate", refers to the asterism in ''Neck'' mansion, containing the stars in Centaurus.〔Allen transliterated 南門 as ''Nan Mun'' in Centaurus. 〕 Allen also suggested that the Babylonian name for the star was "Kakkab Su-gub Gud-Elim" (Star Left Hand of the Horned Bull).〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Alpha Lupi」の詳細全文を読む スポンサード リンク
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